This invention relates to novel 4-benzoylisoxazole derivatives, compositions containing them, processes for their preparation, intermediates in their preparation and their use as herbicides.
Herbicidal 4-benzoylisoxazoles are described in European Patent Publication Numbers 0418175, 0487357, 0527036, 0527037, 0560482, and 0560483.
The present invention provides 4-benzoylisoxazole derivatives of formula (I): 
wherein:
R represents the hydrogen atom or a group xe2x80x94CO2R4;
R1 represents:
a straight- or branched-chain alkyl group containing up to six halogen atoms; or
a cycloalkyl group containing from three to six carbon atoms optionally substituted by one or more R5 groups or one or more halogen atoms;
R2 represents:
a halogen atom;
a straight- or branched-chain alkyl, alkenyl or alkynyl group containing up to six carbon atoms optionally substituted by one or more halogen atoms;
a straight- or branched-chain alkyl group containing up to six carbon atoms which is substituted by one or more groups xe2x80x94OR5; or
a group selected from nitro, cyano, xe2x80x94CO2R5, xe2x80x94S(O)pR6xe2x80x2, xe2x80x94O(CH2)mOR5, xe2x80x94COR5, xe2x80x94NR5R6, xe2x80x94N(R8)SO2R7, xe2x80x94OR5, xe2x80x94OSO2R7, xe2x80x94(CR9R10)tSOqR7 and xe2x80x94CONR5R6;
R3 represents a group xe2x80x94C(Z)xe2x95x90Y;
in which Yxe2x95x90O or S (preferably Y represents O);
Z represents a group R63, xe2x80x94NR60R61, xe2x80x94N(R60)xe2x80x94NR61R62, xe2x80x94SR63, xe2x80x94OR63; wherein R60, R61 and R62 which may be the same or different each represents:
a hydrogen atom, a straight- or branched-chain alkyl, alkenyl or alkynyl group containing up to six carbon atoms optionally substituted by one or more halogen atoms; or a group xe2x80x94(CH2)wxe2x80x94 [phenyl optionally substituted by one to five groups R21];
R63 represents:
a straight- or branched-chain alkyl, alkenyl or alkynyl group containing up to six carbon atoms optionally substituted by one or more halogen atoms, or a group xe2x80x94(CH2)wxe2x80x94[phenyl optionally substituted by one to five groups R21];
X represents a group xe2x80x94N(R8xe2x80x2)xe2x80x94; in which,
R8 represents:
the hydrogen atom;
a straight- or branched-chain alkyl, alkenyl or alkynyl group containing up to ten carbon atoms optionally substituted by one or more halogen atoms;
a cycloalkyl group containing from three to six carbon atoms;
xe2x80x94(CH2)wxe2x80x94[phenyl optionally substituted by from one to five groups R21]; or
a group xe2x80x94OR11;
and the groups R3 and R8xe2x80x2 in the grouping of formula xe2x80x94N(R8xe2x80x2)xe2x80x94R3 may, together with the nitrogen atom to which they are attached, form a 4 to 6 membered ring of formula (AA), (AB), (AC) or (AD): 
wherein
E represents an alkylene or alkylidene chain of 1 or 3 carbon atoms optionally substituted by a group R64 and E1 represents alkyl of 1 or 2 carbon atoms optionally substituted by a group R64, wherein R64 represents an optionally halogenated straight- or branched-chain alkyl group containing up to 6 carbon atoms and R65 represents the hydrogen atom or an optionally halogenated straight- or branched-chain alkyl group containing up to 6 carbon atoms; in formula (AB) the groups Y may be the same or different;
n represents zero or an integer from one to four; where n is greater than one the groups R2 may be the same or different;
R4 represents a straight- or branched-chain alkyl group containing up to six carbon atoms optionally substituted by one or more halogen atoms;.
R5 and R6, which may be the same or different, each represents:
the hydrogen atom,
a straight- or branched-chain alkyl, alkenyl or alkynyl group containing up to six carbon atoms optionally substituted by one or more halogen atoms;
R6xe2x80x2 is as hereinbefore defined for R6 but excluding the hydrogen atom;
R7 represents:
a straight- or branched-chain alkyl, alkenyl or alkynyl group containing up to six carbon atoms optionally substituted by one or more halogen atoms;
a cycloalkyl group containing from three to six carbon atoms;
a group xe2x80x94(CH2)wxe2x80x94[phenyl optionally substituted by from one to five groups R21];
R8 is as hereinbefore defined for R8xe2x80x2;
R9 and R10 represent a group selected from:
the hydrogen atom;
a straight- or branched-chain alkyl group containing up to six (preferably up to 3) carbon atoms optionally substituted by one or more halogen atoms;
R11 represents a straight- or branched-chain alkyl group containing up to six carbon atoms optionally substituted by one or more halogen atoms;
R21 represents:
a halogen atom;
a straight- or branched-chain alkyl group containing up to three carbon atoms optionally substituted by one or more halogen atoms;
or a group selected from nitro, cyano, xe2x80x94S(O)pR5xe2x80x2 and xe2x80x94OR5;
wherein R5xe2x80x2 is as hereinbefore defined for R5 but excluding the hydrogen atom;
m represents one, two or three;
p represents zero, one or two;
q represents zero, one or two;
t represents one, two, three or four (preferably one); and
w represents zero or one;
and agriculturally acceptable salts thereof, which possess valuable herbicidal properties.
Furthermore in certain cases the groups R, R1, R2 and others may give rise to geometric and/or optical isomers. All such forms are embraced by the present invention
By the term xe2x80x9cagriculturally acceptable saltsxe2x80x9d is meant salts the cations or anions of which are known and accepted in the art for the formation of salts for agricultural or horticultural use. Preferably the salts are water-soluble.
The compounds of the invention, in some aspects of their activity, for example in their control of important weeds found in cereal crops, e.g. Galium aparine, Alopecurus myosuroides and Avena fatua (especially Galium aparine), and in their selectivity in important cereal crops, e.g. wheat and maize, show advantages over known compounds.
The compounds are of particular interest against monocotyledonous weeds by post-emergence application.
Preferably the 2-position of the benzoyl ring is substituted, most preferably by the group xe2x80x94XR3.
Preferably the 5- and 6-positions of the benzoyl ring are unsubstituted.
Preferred compounds of formula (I) are those wherein:
R1 represents:
a straight- or branched-chain alkyl group containing up to six carbon atoms which is optionally substituted by one or more halogen atoms; or
a cycloalkyl group containing from three to six carbon atoms optionally substituted by one or more methyl groups or one or more halogen atoms;
R2 represents:
a halogen atom;
a straight- or branched-chain alkyl, alkenyl or alkynyl group containing up to six carbon atoms optionally substituted by one or more halogen atoms;
a straight- or branched-chain alkyl group containing up to six carbon atoms which is substituted by a group xe2x80x94OR5; or
a group selected from nitro, cyano, xe2x80x94CO2R5, xe2x80x94S(O)pR6xe2x80x2, xe2x80x94O(CH2)mOR5, xe2x80x94COR5, xe2x80x94NR8SO2R7, xe2x80x94OR5, xe2x80x94CH2SOqR7;
X represents a group xe2x80x94N(R8xe2x80x2)xe2x80x94; or the groups R3 and R8xe2x80x2 in the grouping of formula xe2x80x94N(R8xe2x80x2)xe2x80x94R3, together with the nitrogen atom to which they are attached, form a ring of formula (AB) above;
Z represents a group R63, xe2x80x94NR60R61, xe2x80x94SR63 or xe2x80x94OR63; and
n represents zero, one, two or three.
A further preferred class of compounds of formula (I) are those wherein:
R1 represents:
methyl ethyl i-propyl, cyclopropyl or 1-methylcyclopropyl;
R2 represents:
a halogen atom;
a straight- or branched-chain alkyl or alkenyl group containing up to four carbon atoms optionally substituted by one or more halogen atoms; or
a group selected from xe2x80x94COR5, xe2x80x94CO2R5, xe2x80x94S(O)pR6xe2x80x2, xe2x80x94CH2SOqR7, xe2x80x94O(CH2)mOR5, xe2x80x94OR5 and xe2x80x94NR8SO2R7;
R5 and R6xe2x80x2, which may be the same or different, each represents:
a straight- or branched-chain alkyl group containing up to three carbon atoms optionally substituted by one or more halogen atoms;
R7 represents:
a straight- or branched-chain alkyl group containing up to four carbon atoms optionally substituted by one or more halogen atoms;
R8 represents:
the hydrogen atom or a straight- or branched-chain alkyl group containing up to four carbon atoms optionally substituted by one or more halogen atoms;
m represents two or three;
q represents zero, one or two;
n represents zero, one or two;
R8xe2x80x2 represents hydrogen or a straight- or branched-chain alkyl group containing up to six carbon atoms optionally substituted by one or more halogen atoms;
Y represents oxygen;
Z represents R63 or xe2x80x94OR63;
in which R63 represents a straight- or branched-chain alkyl group containing up to six carbon atoms optionally substituted by one or more halogen atoms; and
xe2x80x94OR63 represents a straight- or branched-chain alkoxy, alkenyloxy or alkynyloxy group containing up to six carbon atoms optionally substituted by one or more halogen atoms.
A further preferred class of compounds of formula I are those wherein:
R represents hydrogen or xe2x80x94CO2R4 wherein R4 is ethyl;
R1 represents:
methyl, ethyl, i-propyl, cyclopropyl, or 1-methylcyclopropyl;
R2 represents:
a halogen atom;
a straight- or branched-chain alkyl group containing up to four carbon atoms optionally substituted by one or more halogen atoms; or
a group xe2x80x94OR5 or xe2x80x94S(O)pR6xe2x80x2;
in which R5 and R6xe2x80x2, which may be the same or different, each represents:
a straight- or branched-chain alkyl group containing up to three carbon atoms optionally substituted by one or more halogen atoms;
Y represents oxygen;
Z represents:
a group R63 or xe2x80x94OR63; in which R63 represents a straight- or branched-chain alkyl group containing up to six carbon atoms optionally substituted by one or more halogen atoms; and
n represents zero, one or two.
A further preferred class of compounds of formula I are those wherein:
R represents hydrogen or xe2x80x94CO2Et;
R1 represents cyclopropyl or isopropyl;
R2 represents halogen, xe2x80x94OR5, xe2x80x94CF3, methyl or xe2x80x94S(O)pMe;
R8xe2x80x2 represents a straight- or branched-chain alkyl or alkenyl group containing up to four carbon atoms;
Y represents oxygen;
Z represents R63, xe2x80x94SR63 or xe2x80x94OR63;
R63 represents:
a straight- or branched-chain alkyl group containing up to four carbon atoms optionally substituted by one or more halogen atoms;
or phenyl;
R5 represents alkyl containing one or two carbon atoms optionally substituted by one or more halogen atoms;
n represents zero, one or two; and
p represents zero, one or two.
A further preferred class of compounds of formula I are those wherein:
R represents hydrogen;
R1 represents cyclopropyl;
R2 represents halogen;
R8xe2x80x2 represents a straight- or branched-chain alkyl group of one to four carbon atoms;
Y represents oxygen;
Z represents R63 or R63;
in which R63 represents a straight- or branched-chain alkyl group containing up to four carbon atoms optionally substituted by one or more halogen atoms; and
n represents one or two.
Particularly important compounds of formula (I) include the following:
1. 4-[4-chloro-2-(N-methylacetamido)benzoyl]-5-cyclopropylisoxazole;
2. 4-[3,4-dichloro-2-(N-ethyl-N-methoxycarbonylamino)benzoyl]-5-cyclopropylisoxazole;
3. 4-[3,4-dichloro-2-(N-methyl-N-ethoxycarbonylamino)benzoyl]-5-cyclopropylisoxazole;
4. 4-[3,4-dichloro-2-(N-methyl-N-methoxycarbonylamino)benzoyl]-5-cyclopropylisoxazole;
5. 4-[3,4-dichloro-2-(N-methyl-N-isopropyloxycarbonylamino)benzoyl]-5-cyclopropylisoxazole;
6. 4-[4-bromo-3-ethoxy-2-(N-ethyl-N-methoxycarbonylamino)benzoyl]-5-cyclopropylisoxazole;
7. 4-[4-bromo-2-(N-ethyl-N-methoxycarbonylamino)-3-(2,2,2-trifluoroethoxy)benzoyl]-5-cyclopropylisoxazole;
8. 4-[4-bromo-2-(N-ethyl-N-methoxycarbonylamino)-3-methoxybenzoyl]-5-cyclopropylisoxazole;
9. 4-[3,4-dichloro-2-(N-propyl-N-methoxycarbonylamino)benzoyl]-5-cyclopropylisoxazole;
10. 4-(3,4-dichloro-2-(N-isopropyl-N-methoxycarbonylamino)benzoyl]-5-cyclopropylisoxazole;
11. 4-[3,4-dichloro-2-(N-alkyl-N-methoxycarbonylamino)benzoyl]-5-cyclopropylisoxazole;
12. 4-[3,4-dichloro-2-(N-ethyl-N-ethoxycarbonylamino)benzoyl]-5-cyclopropylisoxazole;
13. 4-[3,4dichloro-2-(N-ethyl-N-propyloxycarbonylamino)benzoyl]-5-cyclopropylisoxazole;
14. 4-[3,4dichloro-2-(N-ethyl-N-isopropyloxycarbonylamino)benzoyl]-5-cyclopropylisoxazole;
15. 4-[3,4chloro-2-(N-ethyl-N-n-butyloxycarbonylamino)benzoyl]-5cyclopropylisoxazole;
16. 4-[3,4-dichloro-2-(N-ethyl-N-methoxycarbonylamino)benzoyl]-5-isopropylisoxazole;
17. 4-[4-bromo-3-ethoxy-2-(N-methyl-N-methoxycarbonylamino)benzoyl]-5-cyclopropylisoxazole;
18. 4-[4chloro-2-(N-methyl-N-methoxycarbonylamino)benzoyl]-5-cyclopropylisoxazole;
19. 5-cyclopropyl-4-[3,4-difluoro-2-(N-methyl-N-methoxycarbonylamino)benzoyl]isoxazole;
20. 4-[4-chloro-2-(N-ethyl-N-methoxycarbonylamino)benzoyl]-5-cyclopropylisoxazole;
21. 4-[4-chloro-2-(N-propyl-N-methoxycarbonylamino)benzoyl]-5-cyclopropylisoxazole;
22. 5-cyclopropyl-4-[2-(N-ethyl-N-methoxycarbonylamino)-4-fluorobenzoyl]isoxazole;
23. 5-cyclopropyl-4-[2-(N-ethyl-N-methoxycarbonylamino)-4-trifluoromethylbenzoyl]isoxazole;
24. 5-cyclopropyl-4-[2-(N-ethyl-N-ethoxycarbonylamino)-4-trifluoromethylbenzoyl]isoxazole;
25. 5-cyclopropyl-4-[2-(N-ethyl-N-isopropyloxycarbonylamino)-4-trifluoromethylbenzoyl]isoxazole;
26. 5-cyclopropyl-4-[2-(N-methyl-N-methoxycarbonylamino)-4-trifluoromethylbenzoyl]isoxazole;
27. 4-[4-bromo-2-(N-methyl-N-methoxycarbonylamino)benzoyl]-5-cyclopropylisoxazole;
28. 5-cyclopropyl-4-[4-iodo-2-(N-methyl-N-methoxycarbonylamino)benzoyl]isoxazole;
29. 5-cyclopropyl-4-[2-(N-methyl-N-methoxycarbonylamino)-4-trifluoromethoxybenzoyl]isoxazole;
30. 4-[4-chloro-2-(N-isobutyl-N-methoxycarbonylamino)benzoyl]-5-cyclopropylisoxazole,
31. 4-[3,4-dichloro-2-(N-methyl-N-methylthiocarbonylamino)benzoyl]-5-cyclopropylisoxazole;
32. 5-cyclopropyl-4-[4-methyl-2-(N-methyl-N-methoxycarbonylamino)benzoyl]isoxazole;
33. 5-cyclopropyl-4-[2-(N-ethyl-N-methoxycarbonylamino)-4-methylsulphonylbenzoyl]isoxazole;
34. 5-cyclopropyl-4-[2-(N-ethyl-N-methoxycarbonylamino)benzoyl]isoxazole;
35. 4-[3-chloro-2-(N-ethyl-N-methoxycarbonylamino)-4-(methylthio)benzoyl]-5-cyclopropylisoxazole;
36. 5-cyclopropyl-4-[2-(N-ethyl-N-methoxycarbonylamino)-3,4-difluorobenzoyl]isoxazole;
37. 5-cyclopropyl-4-[2-(N-ethyl-N-methoxycarbonylamino)-3-fluoro-4-(methylthio)benzoyl]isoxazole;
38. 4-[4-chloro-2-(N-ethyl-N-methoxycarbonylamino)-3-fluorobenzoyl]-5-cyclopropylisoxazole;
39. 4-[3,4-dibromo-2-(N-ethyl-N-methoxycarbonylamino)benzoyl]-5cyclopropylisoxazole;
40. 4-[3-chloro-2-(N-ethyl-N-methoxycarbonylamino)benzoyl]-5-cyclopropylisoxazole;
41. 5-cyclopropyl-4-[2-(N-ethyl-N-phenoxycarbonylamino)-4-trifluoromethylbenzoyl]isoxazole;
42. 4-[4-chloro-2-(N-ethyl-N-ethoxycarbonylamino)benzoyl]-5-cyclopropylisoxazole;
43. 4-[4-chloro-2-(N-propyl-N-propyloxycarbonylamino)benzoyl]-5-cyclopropylisoxazole;
44. 4-[4-chloro-2-(N-propyl-N-ethoxycarbonylamino)benzoyl]-5-cyclopropylisoxazole;
45. 4-[4-chloro-2-(N-propyl-N-n-butyloxycarbonylamino)benzoyl]-5-cyclopropylisoxazole;
46. ethyl 4-[3,4-dichloro-2-(N-methyl-N-methoxycarbonylamino)benzoyl]-5-cyclopropylisoxazole-3 -carboxylate;
47. ethyl 4-[3,4-dichloro-2-(N-ethyl-N-methoxycarbonylamino)benzoyl]-5-cyclopropylisoxazole-3-carboxylate;
48. 4-[3-chloro-2-(N-ethyl-N-methoxycarbonylamino)-4-methylsulphonylbenzoyl]-5-cyclopropylisoxazole;
49. 5-cyclopropyl-4-[2-(N-ethyl-N-methoxycarbonylamino)-3-fluoro-4-methylsulphonylbenzoyl]isoxazole; and
50. 5-cyclopropyl-4-[2-(N-ethyl-N-methoxycarbonylamino)-3-fluoro-4-methylsulphinylbenzoyl]isoxazole.
The numbers 1 to 50 are assigned to these compounds for reference and identification hereinafter.
Compounds of formula (I) may be prepared by the application or adaptation of known methods (i.e. methods heretofore used or described in the literature), for example as hereinafter described.
In the following description where symbols appearing in formulae are not specifically defined, it is to be understood that they are xe2x80x9cas hereinbefore definedxe2x80x9d in accordance with the first definition of each symbol in the specification.
It is to be understood that in the descriptions of the following processes the sequences may be performed in different orders, and that suitable protecting groups may be required to achieve the compounds sought.
According to a feature of the present invention compounds of formula (I) in which R represents hydrogen may be prepared by the reaction of a compound of formula (II): 
wherein L is a leaving group and R1, R2, R3, n and X are as hereinbefore defined with hydroxylamine or a salt of hydroxylamine. Hydroxylamine hydrochloride is generally preferred. Generally L is alkoxy, for example ethoxy, or N,N-dialkylamino, for example dimethylamino. The reaction is generally carried out in an organic solvent such as ethanol or acetonitrile or a mixture of a water-miscible organic solvent and water, preferably in a ratio of organic solvent: water of from 1:99 to 99:1, optionally in the presence of a base or acid acceptor such as triethylamine or sodium acetate at a temperature from room temperature to the boiling point of the solvent. The intermediates of formula (II) are novel and as such constitute a further feature of the present invention.
According to a further feature of the present invention compounds of formula (I) in which R represents hydrogen may be prepared by the reaction of a compound of formula (III): 
wherein R1 is as hereinbefore defined and Yxe2x80x2 represents a carboxy group or a reactive derivative thereof (such as a carboxylic acid chloride or carboxylic ester), or a cyano group, with an appropriate organometalic reagent such as a Grignard reagent or an organolithium reagent. The reaction is generally carried out in an inert solvent such as ether or tetrahydrofuran at a temperature from 0xc2x0 C. to the reflux temperature of the mixture.
According to a further feature of the present invention compounds of formula (I) wherein R represents a group xe2x80x94CO2R4 may be prepared by the reaction of a compound of formula (IV) 
wherein R1, R2; R3, X and n are as hereinbefore defined and P is a leaving group such as N,N-dialkylamino, with a compound of formula R4O2CC(Zxe2x80x2)xe2x95x90NOH wherein R4 is as hereinbefore defined and Zxe2x80x2 is a halogen atom. Generally Zxe2x80x2 is chlorine or bromine. The reaction is generally performed in an inert solvent such as toluene or dichloromethane either in the presence of a base such as triethylamine or a catalyst such as a 4 Angstrom molecular sieve or fluoride ion.
According to a further feature of the present invention compounds of formula I in which R represents a group xe2x80x94CO2R4 may be prepared by the reaction of a compound of formula (V): 
wherein R1, R2, R3, X and n are as hereinbefore defined with a compound of formula R4O2CC(Zxe2x80x2)xe2x95x90NOH wherein Zxe2x80x2 and R4 are as hereinbefore defined. The reaction is generally performed in an inert solvent such as toluene or dichloromethane optionally in the presence of a base such as triethylamine or a catalyst such as a 4 Angstrom molecular sieve or fluoride ion. The reaction can be carried out at a temperature between room temperature and the reflux temperature of the mixture.
According to a further feature of the present invention compounds of formula (I) wherein R represents xe2x80x94CO2R4 may be prepared by the reaction of a salt of compounds of formula (VI): 
wherein R1, R2, R3, X and n are as hereinbefore defined with a compound of formula R4O2CC(Zxe2x80x2)xe2x95x90NOH wherein R4 and Zxe2x80x2 are as hereinbefore defined. Preferred salts include sodium or magnesium salts. The reaction may be performed in an inert solvent such as dichloromethane or acetonitrile at a temperature between room temperature and the reflux temperature of the mixture. The salt of a compound of formula (VI) is generally prepared in situ by treating the compound of formula (VI) with a base. Examples of suitable bases include alkaline earth metal alkoxides such as magnesium methoxide.
According to a further feature of the present invention compounds of formula (I) in which X represents xe2x80x94NHxe2x80x94 may be prepared by the deprotection of a compound of formula (VII): 
wherein R, R1, R2 and n are as hereinbefore defined and A represents xe2x80x94NX1R3 wherein R3 is as hereinbefore defined and X1 represents a protecting group which can be removed under acidic or neutral reaction conditions. The protecting group may be for example a benzyl group (which may be removed by hydrogenolysis) or a t-butyloxycarbonyl group (t-BOC). Suitable methods of protection and deprotection are described in the literature (for example in xe2x80x9cProtective Groups in Organic Synthesisxe2x80x9d, by T. W. Greene and P. G. M. Wuts). The intermediates of formula (VII) are novel and as such constitute a further feature of the present invention.
According to a further feature of the present invention compounds of formula (I) in which R3 represents a group xe2x80x94C(Z)xe2x95x90Y and Z is selected from R63, xe2x80x94NR60R61 (wherein R60 and R61 are not hydrogen), xe2x80x94SR63 or xe2x80x94OR63 may be prepared by the reaction of a compound of formula (VIII): 
with a compound of formula A1xe2x80x94CZ(xe2x95x90Y), wherein A1 is a leaving group and Z is as defined above. Preferably A1 is chlorine. The reaction is generally performed in the presence of a weak base, e.g. caesium carbonate and in an inert solvent (e.g. acetonitrile) at a temperature from room temperature to reflux.
According to a further feature of the present invention compounds of formula (I) in which R3 represents a group xe2x80x94C(Z)xe2x95x90Y and Z is xe2x80x94NHR60 may be prepared by the reaction of the corresponding compound of formula (VII) with a compound of formula R60xe2x80x94Nxe2x95x90Cxe2x95x90Y, wherein R60 is as hereinbefore defined. The reaction is generally performed in an inert solvent at a temperature from room temperature to reflux.
Intermediates in the preparation of compounds of formula (I) may be prepared by the application or adaptation of known methods.
Compounds of formula (II) may be prepared by the reaction of compounds of formula (VI) with either a trialkyl orthoformate such as triethyl orthoformate or a dimethylformamide dialkyl acetal such as dimethylformamide dimethyl acetal
The reaction with a trialkyl orthoformate can be carried out in the presence of acetic anhydride at the reflux temperature of the mixture and the reaction with dialkylformamide dialkyl acetal is carried out optionally in the presence of an inert solvent at a temperature from room temperature to the reflux temperature of the mixture.
Compounds of formula (IV) may be prepared by the reaction of a compound of formula R1C(P)xe2x95x90CH2 with a benzoyl chloride of formula (IX): 
The reaction is generally carried out in the presence of an organic base such as triethylamine in an inert solvent such as toluene or dichloromethane at a temperature between xe2x88x9220xc2x0 C. and room temperature.
Compounds of formula (V) may be prepared by the metallation of the appropriate acetylene of formula (X):
R1Cxe2x89xa1CHxe2x80x83xe2x80x83(X)
followed by reaction of the metal salt thus obtained with a benzoyl chloride of formula (IX). The metallation is generally performed using n-butyl lithium in an inert solvent such as ether or tetrahydrofuran at a temperature from xe2x88x9278xc2x0 C. to 0xc2x0 C. The subsequent reaction with the benzoyl chloride is carried out between xe2x88x9278xc2x0 C. and room temperature.
Compounds of formula (VI) may be prepared by the reaction of an acid chloride of formula (IX) with the metal salt of a compound of formula (XI):
R1COCH2CO2tBuxe2x80x83xe2x80x83(XI)
wherein R1 is as hereinbefore defined, to give a compound of formula (XI): 
wherein R1, R2 R3, X and a are as hereinbefore defined, which is subsequently decarboxylated to give a compound of formula (VI). Generally the reaction to produce the compound of formula (XII) is performed in a solvent such as a lower alcohol, preferably methanol, in the presence of a metal preferably magnesium. The reaction may also be performed using a pre-prepared metal salt of a compound of formula (XI). The decarboxylation is generally performed by refluxing the compound of formula (XII) in the presence of a catalyst, such as paratoluenesulphonic acid or trifluoroacetic acid, in an inert solvent e.g. toluene or 1,2-dichloroethane.
Compounds of formula (VI) may also be prepared by the reaction of a benzoic acid ester of formula (XV): 
wherein R2, R3, X and n are as hereinbefore defined and R12 represents a lower alkyl group, with a compound of formula (XIV):
R1C(O)CH3xe2x80x83xe2x80x83(XIV)
wherein R1 is as hereinbefore defined. The reaction is generally performed in a solvent such as ether, tetrahydrofuran or N,N-dimethylformamide, in the presence of a base, preferably an alkali metal base such as sodium hydride, at a temperature from 0xc2x0 C. to the reflux temperature.
Compounds of formula (VI) in which xe2x80x94XR3 represents xe2x80x94NHCONR60R61 may also be prepared by the reaction of a compound of formula (XV): 
with a ketone of formula (XIV) above in the presence of a base, preferably lithium diisopropylamide in an inert solvent at a temperature from 78xc2x0 C. to room temperature.
Compounds of formula (VII) may be prepared by the processes hereinbefore described for preparing compounds of formula (I) in which R, R1, R2 and n are as hereinbefore defined and the group xe2x80x94XR3 is replaced by the group A.
Compounds of formula (VIII) may be prepared by the hydrolysis of the corresponding compound of formula (I) in which R3 is replaced by a protecting group, for example alkylsulphonyl (preferably methylsulphonyl). The hydrolysis is generally performed using an acid, preferably sulphuric acid, in an inert solvent (e.g. acetic acid) at a temperature from room temperature to reflux. Compounds of formula (I) in which R3 is replaced by a protecting group may be prepared by the processes hereinbefore described for preparing compounds of formula (I) in which R, R1, R2 and n are as hereinbefore defined and the group R3 is replaced by a protecting group.
Acid chlorides of formula (IX) may be prepared by the reaction of a benzoic acid of formula (XVI): 
with a chlorinating agent, for example thionyl chloride at the reflux temperature of the mixture. In some cases the benzoyl chlorides may also be prepared by reaction of the benzoic acid with oxalyl chloride in a solvent such as 1,2-dichloroethane at from ambient to reflux temperature.
A number of the benzoic acids of formula (XVI) are novel and as such constitute a flirter feature of the present invention. Compounds of formula (XVI) in which R2 represents a halogen atom or a group selected from trifluoromethyl, methyl, C1-2 haloalkoxy and S(O)pMe wherein p is zero, one or two; X represents xe2x80x94NR8xe2x80x2 wherein R8 represents alkyl or alkenyl containing up to four carbon atoms optionally substituted by one or more halogen atoms; n represents one or two; R3 represents xe2x80x94C(Z)xe2x95x90Y wherein Y is oxygen, Z is R63 or xe2x80x94OR63 and R63 represents alkyl containing up to four carbon atoms optionally substituted by one or more halogen atoms, are especially preferred.
Compounds of formula (XV) may be prepared by the application or adaptation of known methods, for example as described in Acta. Chim. Acad. Sci. 107(1), 57 (1981).
Compounds of formula (XVI) in which the group xe2x80x94XR3 is ortho to the acid group and R3 is xe2x80x94C(O)R63 may be prepared by the reaction of a compound of formula (XVII): 
wherein X2 is chlorine or preferably bromine or iodine, with a compound of formula R8xe2x80x2NHC(O)R63 in the presence of a strong base. Generally the reaction is performed in the presence of a catalyst e.g. copper (I) chloride or preferably copper (I) bromide or iodide, in an inert solvent such as dioxan or toluene. The preferred strong base is sodium hydride and the reaction is conveniently performed at a temperature from 50xc2x0 C. to reflux
Intermediates of formula (VI) in which the group xe2x80x94XR3 is ortho to the carbonyl group and represents a group R8xe2x80x2NC(O)R63 may be prepared by the reaction of a compound of formula (XVIII): 
wherein X2 is chlorine or preferably bromine or iodine, with a compound of formula R8xe2x80x2NHC(O)R63 in the presence of a strong base. Generally the reaction is performed in the presence of a catalyst e.g. copper (I) chloride or preferably copper (I) bromide or iodide, in an inert solvent such as dioxan or toluene. The preferred strong base is sodium hydride and the reaction is conveniently performed at a temperature from 50xc2x0 C. to reflux.
Intermediates of formula (XVI) in which R3 represents xe2x80x94CO2R63 may be prepared by the reaction of the corresponding compound of formula (XVI) in which R3 represents hydrogen with a compound of formula Clxe2x80x94CO2R63 in the presence of a base. The base may be pyridine or triethylamine or preferably an alkali metal carbonate e.g. sodium carbonate and the reaction is performed in an inert solvent (e.g. water) at a temperature from 0xc2x0 C. to 100xc2x0 C., for example according to the method described in Org. Synthesis Coll. Vol. 3, 167.
Intermediates of formula (M), (X), (XI), (XIII), (XIV), (XVII) and (XVM) are known or may be prepared by the application or adaptation of known methods.
Agriculturally acceptable salts of compounds of formula (I) may be prepared by the application or adaptation of known methods.
Those skilled in the art will appreciate that some compounds of formula (I) may be prepared by the interconversion of other compounds of formula (I) and such interconversions constitute yet more features of the present invention. Examples of such interconversions are hereafter described.
According to a further feature of the present invention compounds in which p and/or q is one or two may be prepared by the oxidation of the sulphur atom(s) of the corresponding compounds in which p and/or q is 0 or 1. The oxidation of the sulphur atom(s) is generally carried out using for example 3-chloroperoxybenzoic acid in an inert solvent such as dichloromethane at a temperature from xe2x88x9240xc2x0 C. to room temperature.